BE1018587A3 - DRYER FOR COMPRESSED GAS AND METHOD FOR DRYING COMPRESSED GAS. - Google Patents

Abstract

Compressed gas dryer, which dryer (1) is provided with a housing (2) containing a drying zone (3) and a regeneration zone (4), and a drum (5) rotating in the housing (2) that is filled with a drying means (6) and drive means (7) for rotating the drum (5) such that the drying means (6) is successively moved through the drying zone (3) and the regeneration zone (4), characterized in that said regeneration zone (4) comprises at least two sub-zones (41, 42), respectively, a first sub-zone (41) through which gas is controlled at a first temperature (T1) and a second sub-zone (42) through which gas is controlled at a second temperature (T2), the second temperature (T2) is higher than the first temperature (T1).

Description

Compressed gas dryer and method for drying compressed gas.

The present invention relates to a compressed gas dryer and to a method for drying a compressed gas.

More specifically, the invention relates to a dryer which essentially consists of a rotating drum provided with regenerable drying agent, which drying agent is alternately passed through two zones of the dryer by rotating the drum, said drying agent being mentioned in one zone, in particular the drying zone. is used to dry a compressed gas and in the other zone, in particular the regeneration zone, said drying agent is regenerated by bringing it into contact with a hot gas.

Because the tumble dryer usually rotates slowly continuously, but sometimes also in a jerky manner, a freshly dried desiccant will end up in the drying zone.

Traditionally, the majority of the compressed gas is cooled and then passed through the drying zone of the dryer, with the drying agent present in the drying zone extracting moisture from this gas, resulting in a dry gas with low pressure dew point.

The remaining part of the compressed gas is sent through the regeneration zone of the dryer, this hot gas evaporating the moisture present in the drying agent, whereby the drying agent is regenerated and then reused in a new cycle in the drying zone to make it compressed. to dry gas.

It is clear that the heat from the compressed gas is used to regenerate the desiccant in the regeneration zone, it being noted that as the temperature of the compressed gas increases, the drying process improves and the efficiency of the installation will be correspondingly increase.

The temperature of the compressed gas used for regeneration can be increased by placing a heating element before passing this gas through the regeneration zone.

The efficiency of the adsorption dryer can thus be increased, which means in concrete terms that a lower pressure dew point for the dried gas can be obtained. For example, under certain circumstances, the pressure dew point can be -25 ° C and the regeneration temperature 150 ° C. By adding a heating element and increasing the regeneration temperature by 30 ° C to 180 ° C, the pressure can be reduced by 10 ° C to -35 ° C.

In turbochargers and low-pressure applications, the temperature of the compressed gas is often too low to be able to regenerate adequately, the compressed gas also having to be heated by heating elements before being passed through the regeneration zone of the dryer.

A drawback is that a heating element consumes a lot of power. Typically, that power consumption is 8 to 15% of the nominal energy and / or power consumption of the compressor, which is a relatively high percentage.

An additional disadvantage is that such a heating element is large and expensive.

The dryer and method according to the invention aims at remedying one or more of the aforementioned and / or other disadvantages.

To this end the invention relates to a compressed gas dryer, which dryer is provided with a housing containing a drying zone and a regeneration zone, and a drum rotating in the housing that is filled with a regenerable drying agent and drive means for rotating the drum such that it desiccant is successively moved through the drying zone and the regeneration zone, said regeneration zone comprising at least two sub-zones, respectively a first sub-zone through which gas is controlled at a first temperature and a second sub-zone through which gas is controlled at a second temperature, the second temperature being higher then the first temperature.

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An advantage of a dryer according to the invention is that the gas to be dried can be dried with greater efficiency in that two sub-zones are realized in the regeneration zone, wherein the temperature of the gas used for the regeneration is different in each sub-zone.

Another advantage is that it is not the entire gas flow that flows through the regeneration zone that has to be heated, but only that part of the gas flow must be heated at a higher temperature or that the remaining flow must be heated less. This allows a considerable energy saving.

This entails numerous advantages because a smaller heating element can be used, resulting in an energy and material cost saving and in a more compact installation.

The invention also relates to a method for drying a compressed gas by means of a dryer which is provided with a housing comprising a drying zone and a regeneration zone and in the housing a rotating drum with a regenerable drying agent and drive means for rotating the drum, wherein the drying agent is successively moved through the drying zone and the regeneration zone and wherein this method comprises the steps of passing the compressed gas to be dried through the drying zone and sending an amount of gas through the regeneration zone for regenerating the drying agent, characterized in that the method further comprises the step of dividing the regeneration zone into at least two sub-zones, a first zone and a second zone, respectively, and of sending a quantity of gas through the first zone to a first temperature Ti and through the second send a quantity of gas to a second temperature T2 in which zone second temperature T2 is higher than the first temperature Ti.

With the insight to better demonstrate the characteristics of the invention, some preferred embodiments of a dryer according to the invention, as well as a method for drying a compressed gas, are described below with reference to the accompanying drawings, in which: figure 1 schematically represents a part of a dryer according to the invention; figure 2 represents a variant of figure 1; Figures 3 and 4 represent the dryer according to Figures 1 and 2, respectively, in an unrolled version.

Figure 1 shows a compressed gas dryer 1 according to the invention. The dryer 1 is provided with a housing 2 containing a drying zone 3 and a regeneration zone 4.

Arranged in housing 2 is a rotating drum 5 which is filled with a drying agent 6. The dryer 1 is also provided with driving means 7 for rotating the drum 5, for example in the form of an electric motor, such that it desiccant 6 is successively moved through the drying zone 3 and the regeneration zone 4.

The drying agent 6 used in the invention is typically a material with high adsorption or absorption potential. Typically, these are granular materials with a high content of internal contact surface, the porous contact surface absorbing moisture when the gas is passed through the drying zone 3. Examples of such materials are active alumina (an amorphous aluminum oxide in an unstable state), silica gels and zeolites.

During the use of the dryer 1, a quantity of gas is passed through the drying zone 3, in this case in the sense indicated by arrow A. This is also illustrated with reference to figure 3.

The above-mentioned regeneration zone 4 comprises at least two sub-zones 41 and 42, respectively a first sub-zone 41 through which gas is controlled at a first temperature T1, in this case according to arrow Bif and a second sub-zone 42 through which gas is controlled at a second temperature T2, in this case example according to the sentence indicated by arrow B2, wherein, according to the specific feature of the invention, the second temperature T2 is higher than the first temperature Ti.

In a preferred embodiment of the invention, the circumferential angle described by the second sub-zone 42 is understood to be between 5 ° and 30 °, more preferably between 15 ° and 20 °.

By the aforementioned circumferential angle is meant here the angle described by a segment of the second sub-zone 42, which segment is formed in a plane perpendicular or substantially perpendicular to the height direction of the drum 5, or in other words perpendicular or substantially perpendicular on the axis of rotation of this drum 5.

Preferably, the aforementioned second sub-zone 42 is provided near the end of the regeneration zone. ~ ·

With the terminology "the end of the regeneration zone" is meant the area of the regeneration zone 4 in which the regenerated drying agent is located before it leaves the regeneration zone 4 to be subsequently introduced into the drying zone 3.

Consequently, the drum rotates. 5, preferably in the sense of the arrow R in Figure 1. It follows that the drying agent 6 moves through the dryer in the sense of the arrow R in Figure 3. In this way the second sub-zone 42 is located at the end of the regeneration zone 4.

In a preferred embodiment, the drying drum 5 is largely cylindrical and the different zones are axially separated in a known manner.

The method for drying a compressed gas by means of a dryer 1 according to the invention is simple and as follows.

The drum 5 is rotated with the driving means 7, as a result of which the drying agent 6 is successively moved through the drying zone 3 and the regeneration zone 4.

A compressed gas or mixture of gases such as air to be dried is initially cooled and then passed through the drying zone 3, in this example according to arrow A in figure 1.

An amount of gas is sent through the regeneration zone 4 to regenerate the drying agent 6, wherein. through the first sub-zone 41 according to arrow Βχ an amount of gas is controlled at a first temperature T1 and through the second sub-zone 42 an amount of gas is controlled at a second temperature T2 according to arrow B2.

It is the essence of the invention that the second temperature T2 is higher than the first temperature T1.

Drying of the compressed gas is carried out more efficiently with the method according to the invention than with conventional methods for drying a compressed gas by means of a tumble dryer, because only the gas in the second sub-zone 42 is heated to a temperature T2, for example by means of a heating element provided for this purpose, which is not shown in the figures.

A possible consequence is, for example, that a sufficient regeneration is obtained in the regeneration zone 4 of the drying agent 6 without a heating element having to be provided for the first sub-zone 41.

Either way, energy will be saved because the entire regeneration flow does not have to be heated to temperature T2.

In case the dryer 1 is used for drying a compressed gas such as compressed air from a compressor, regeneration gas flow can be used to regenerate the drying agent which is formed by a portion of the gas that is just after, or with in other words, it is branched downstream of the compressor and then passed through the regeneration zone.

Because of the presence of the compression heat, this portion of the gas is at a high temperature, as a result of which this portion of gas can contain much moisture.

However, it is not excluded according to the invention to supply the regeneration gas from elsewhere, for example from a separate compressed air source.

In the case of the aforementioned arrangement with the supply of a compressed gas to be dried, such as compressed air, originating from a compressor, the part of the gas tapped after the compressor that is led to the regeneration zone is preferably split into two gas flows, respectively first gas stream that is passed through the first sub-zone 41 of the regeneration zone 4, and a second gas stream that is further heated by means provided for this purpose, for example in the form of a heating element, and which is subsequently passed through the second sub-zone 42 of the regeneration zone 4 is being sent.

Figures 2 and 4 show an alternative embodiment of a dryer 1 according to the invention in which in this case, (in addition to the divided regeneration zone 4, the drying zone 3 is divided into a first zone 30 and a second zone 31. ·

The method of drying a compressed gas by means of a dryer as shown in Figure 2 is substantially identical to the method as discussed above with regard to the first embodiment of Figure 1.

In this case a gas with a third temperature To is sent through the first zone 30 of the drying zone 3, for example, but not necessarily according to the sentence indicated by arrow A0.

A gas with a third temperature also becomes through the second zone 31 of the drying zone 3. TD controlled, for example according to the sentence indicated with arrow A.

Preferably, the temperature T0 in the first zone 30 differs from the temperature TD in the second zone 31. More specifically, T0 is preferably smaller than TD.

According to another preferred feature of the invention, the drum 5 rotates in the sense of arrow R, as shown in Figure 2. In this way, the drying means 6 is successively moved through the first sub-zone 41 and the second sub-zone 42 of the regeneration zone 4 to subsequently to be passed through the first zone 30 and the second zone 31 of the drying zone 3. The preferred. flow sense of the drying agent 6 through the dryer 1 is also represented by arrow R in figure 4.

In a practical embodiment of the invention, the peripheral angle described by the first zone 30 is smaller than the peripheral angle described by the second zone 31.

However, the present invention does not exclude that the drying zone 3 and / or the regeneration zone 4 comprise more than two zones 30-31 and 41-42, respectively.

It is also obvious that the presence of a zone 30 is not a strict requirement for the invention.

The meaning of arrows A, Blf B2 and A0 can be changed independently of each other.

It is also clear that the quantities of gas sent through the different zones can differ from one another, with factors such as the flow rate and the size of the respective zone being important.

The present invention is by no means limited to the embodiments described as examples and shown in the figures, but such a dryer for compressed gas can be realized according to different variants without departing from the scope of the invention.

Claims (13)

A compressed gas dryer, said dryer (1) comprising a housing (2) containing a drying zone (3) and a regeneration zone (4), and a drum (5) rotating in the housing (2) that is filled with a regenerable drying means (6) and drive means (7) for rotating the drum (5) such that the drying means (6) is successively moved through the drying zone (3) and the regeneration zone (4), characterized in that said regeneration zone (4) comprises at least two sub-zones (41, 42), respectively a first sub-zone (41) through which gas is controlled at a first temperature (T1) and a second sub-zone (42) through which gas is controlled at a second temperature (T2), wherein the second temperature (T2) is higher than the first temperature (Τχ). Dryer according to claim 1, characterized in that the second sub-zone (42) is located near the end of the regeneration zone (4). is located. Dryer according to one of the preceding claims, characterized in that the drying zone (3) comprises at least two sub-zones, a first zone (30) and a second zone (31) respectively. Dryer according to claim 3, characterized in that gas is sent through the first zone (30) of the drying zone (3) to a third temperature (T0) that differs from the fourth temperature (TD) of the gas passing through the second zone (31) from the drying zone (3). . Dryer according to claims 3 or 4, characterized in that the drying agent (6) is successively moved through the first zone (30) and the second zone (31) of the drying zone (3). Dryer according to one of claims 3 to 5, characterized in that the first zone (30) of the drying zone (3) describes a circumference angle that is smaller than the circumference angle of the second zone (31) of the drying zone (3) ). Dryer according to one of the preceding claims, characterized in that said second sub-area (42) has a. describes a circumference angle comprised between 5 ° and 30 °. Dryer according to one of the preceding claims, characterized in that the aforementioned second sub-area (42) describes a circumference angle which is included between 15 ° and 20 °. Dryer according to one of claims 1 to 8, characterized in that it comprises a heating element for heating the gas that will be sent through the second sub-zone (42). Method for drying a compressed gas by means of a dryer (1) which is provided with a housing (2) containing a drying zone (3) and a regeneration zone (4) and a drum rotating in the housing (2) 3) with a regenerable drying agent (6) and drive means (7) for rotating the drum (3) such that the drying agent / (6) is successively moved through the drying zone (3) and the regeneration zone * (4), method comprises the steps of passing the compressed gas to be dried through the drying zone (3) and passing an amount of gas through the regeneration zone (4) for regenerating the drying agent, characterized in that the method further comprises the step of the regeneration zone ( 4) divide into at least two sub-zones (41, 42), a first sub-zone (41) and a second sub-zone (42), respectively, and send a quantity of gas through the first sub-zone to a first temperature (Ti) and through the second sub-zone (42) e and controlling an amount of gas to a second temperature (T2), the second temperature (T2) being higher than the first temperature (T1). Method according to claim 10, characterized in that the drying zone (3) comprises at least two zones, a first zone (30) and a second zone (31), respectively; and that the method additionally consists of passing a gas at a third temperature (To) through the first zone (30) of the drying zone (3) that differs from a fourth temperature (TD) of a gas passing through the second zone (31) from the drying zone (3). Method according to claim 10 or 11, characterized in that it is used for drying compressed gas from a compressor; and that a portion of said compressed gas is passed through said regeneration zone (4) for regeneration of the drying agent, said compressed gas being tapped just after the compressor. Method according to claim 12, characterized in that the temperature difference between the first temperature (Τχ) and the second temperature (T2) of the gas flow through the regeneration zone (4) is achieved by the gas passing through the second sub-zone (42) to heat more than the gas flow that is sent through the first sub-zone (41).